Air compressor apparatus and method



Aug. 19, 1969 I J. E. GRIMMERI 3,462,074;

AIR COMPRESSOR APPARATUS AND METHOD Filed Feb. 25, 1968 I 2 Sheets-Sheet 1 Fig.3

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United States Patent 3,462,074 AIR COMPRESSOR APPARATUS AND METHOD John E. Grimmer, 9763 Eastridge Drive, El Paso, Tex. 79925 Filed Feb. 23, 1968, Ser. No. 707,698 Int. Cl. F04b 27/00, 39/12 US. Cl. 230-181 15 Claims ABSTRACT OF THE DISCLOSURE Multiple chamber reciprocating type compressor apparatus including air receiving chamber arranged to receive compressed air passed through outlets of each compression chamber. Air receiving chamber having a series of interconnected venturi-like internal passage portions disposed along its lengthwise extent, each suitably arranged in receiving relation to a compression chamber air outlet so that compressed air discharge through one compression chamber air outlet into receiving chamber produces air flow in a venturi-like passage portion of other of said outlets with a corresponding reduction in pressure in area of other said outlets. Preselected succession of compressed air discharges in direction of outlet of receiving chamber producing cumulative effect on velocity of air flow in each succeeding venturi-like passage portion. Cylinder head apparatus including air receiving chamber, air inlets, air outlets, cooling jacket for receiving chamber and seat for valve mechanism for each compression chamber formed as a body arranged to mount in a closing relation to upper portons of multiple compression chambers.

This invention relates to the compression of air and more particularly to a novel reciprocating type air compressor apparatus.

There is an increasing demand for higher capacity mobile compressors in a variety of fields including mining, construction, drilling work and the like. The external power, usually an internal combustion engine, which is required to drive a compressor to deliver a particular amount of air at a particular discharge pressure affects its bulk and size and thus its suitability for portable or mobile applications. Specifically, the industry standard for horsepower requirements for a single stage reciprocating type compressor is about 22 BHP per 100 c.f.m. at 100 p.s.i.g. discharge pressure. Single stage reciprocating air compressors have not been entirely suitable for producing the higher air capacity outputs because of the low volumetric efliciency and typically multistage compressors have been used which necessitate additional bulk, weight and cost. The industry standard for such single stage compressors is about 55% at 100 p.s.i.g. discharge pressure.

Accordingly, an object of this invention is to provide a simple, durable and efiicient air compressor apparatus having a higher air output capacity for a given weight, bulk and horsepower requirement than previous air compressors.

Another object of this invention is to provide compressor apparatus including a receiving chamber arranged to receive the compressed air discharge from a bank or multiple compression chambers which is particularly suitable for mobile air compressor applications.

Another object of this invention is to provide a novel method of increasing the output capacity of a single 1' multi-stage reciprocating type air compressor.

A further object of this invention is to provide cylinder head apparatus for a multiple chamber compressor which in additon to functioning as a closure for each compression chamber uses the discharge air flow of one compression chamber to promote increased air output from others of the compression chambers.

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Yet another object of this invention is to provide cylinder head apparatus for a multiple chamber compressor having wall portions which in addition to functioning as a closure for the top portion of each chamber includes an air receiving chamber arranged for receiving the air discharge from all of the compressor chambers and a single cooling jacket for cooling the air in this receiving chamber.

Other objects, advantages and capabilities of the present invention will become more apparent as the description proceeds taken in conjunction with the accompanying drawings in which:

FIG. 1 is a schematic diagram of a mobile single stage compressor system embodying features of the present invention;

FIG. 2 is a bottom plan view of cylinder head apparatus arranged for detachably mounting on the compressor side of the cylinder block of FIG. 1 embodying features of the present invention;

FIG. 3 is a sectional view taken along lines 3-3 of FIG. 2 showing air flow inlets, outlets and coolant flow passages formed in the cylinder head apparatus with a typical unloader valve and pressure operated valve assembly and a cylinder block forming the compressor chamber illustrated in operative association therewith;

FIG. 4 is a top plan view of the cylinder head apparatus of FIG. 2;

FIG. 5 is a side elevation view of the cylinder head apparatus of FIG. 2;

FIG. 6 is a sectional view taken along lines 6-6 of FIG. 5 with the air flow indicated by arrows; and

FIG. 7 is a comparison of performance between known single stage compressors and a single stage compressor embodying features of the present invention.

Referring now to the drawing, in FIG. 1 there is depicted in generally schematic form a mobile type compressor system which is typical of that with which the compressor cylinder head apparatus shown in detail in FIGS. 2 through 6 may be operatively associated. The cylinder block 11 is shown as of the V-8 type having four cylinders on one side beingof the usual engine construction forming the power side or power bank 12 and four cylinders in the cylinder block on the other side equipped with air compressor components forming the compressor side or bank 13 with the pistons on each side being joined by a common crankshaft 14 so the power side 12 rotates the crankshaft 14 to drive the compressor side 13. While a V-8 type cylinder block is one preferred arrangement, particularly for the head apparatus shown, it is understood that other V types, in-line types or a separate engine suitably coupled to a separate recip rocating type compressor may also be used.

The power side 12 has the usual internal combustion type cylinder head 15, an air intake manifold 16 and an exhaust manifold 17 mounted on the cylinder head 15. The compressor side 13, in a preferred arrangement, has cylinder head apparatus generally depicted by numeral 20 and which is arranged for mounting on the cylinder block like the internal combustion type by bolting into the block and has an air intake manifold 18 mounted directly on top of this compressor head apparatus 20. Both the power and compressor banks draw incoming air through separate air cleaners (not shown) and induction systems. Air, at near atmospheric pressure, enters the power side 12 through intake manifold 16 and enters the compressor side 13 through intake manifold 18.

In general, compressed air from the compressor cylinders flows into the cylinder head apparatus 20 which inter alia, is a primary receiver chamber and is passed through an outlet 19 at one end thereof and is then delivered to a secondary storage or receiving tank 21 by a suitable flow line. A line 25 extending from the storage tank 21 to the compressor :bank 13 is used to depict schematically a cut-off control for the unloader valve when the tank 21 has a preset pressure such as 100 p.s.i.g.

A fan blade 22 is coupled to the forward end of the crankshaft 14, a radiator 23 is disposed forwardly of the fan blade and there is provided with a flywheel 24 mounted on the rear end of the crankshaft 14. A preferred cooling arrangement for the engine and compressor includes a water pump 26 preferably driven from the crankshaft 14 which pumps water from the radiator 23 through suitable flow lines shown to and then through water jackets in the engine block of both the compressor side 13 and the engine side 12 as is generally depicted in dash lines. A flow line 27 returns flow from the compressor section 13 directly to the radiator. A thermostat valve 28 is arranged in the flow line 29 which returns flow from the engine section to the radiator. The thermostat valve 28 in a preferred arrangement is normally closed and the total flow from the pump goes to the compressor side and opens only upon load demands to maintain the engine side at about 170 F. to 180 F.

This combined V-8 type engine and compressor assembly depicted in FIG. 1 for mobile usage is mounted on a vehicular frame schematically depicted by numeral 30 which may be a skid-type frame or a rubber tired chassis so that it may be easily transported to the point of use. For self-powered transport there may be provided a vehicle power transmission assembly including a transmission 31 suitably coupled to a differential 32 for a set of ground contacting wheels 33 and 34 mounted on frame 30. A suitable shaft coupling portion 35 on the flywheel 24 may be utilized to connect with a clutch coupling portion 36 on the input shaft of the transmission 31.

Referring now particularly to FIGS. 2-6, there is shown a four cylinder compressor head apparatus 20 constructed as a body formed as by fabrication or casting and arranged with a flat bottom surface to seat on the top or open end of a compressor chamber block which in the form shown is one side of a V-8 cylinder block designated 13 in FIG. 3. The head apparatus 20 is provided with a plurality of bolt holes 41 preferably arranged in a circumferential pattern about the central openings or air inlet passages described hereafter and are adapted to slidably receive bolts or the like which thread into the associated block with a suitable sealing gasket between the head apparatus 20 and the block 13 in a manner similar to that used in conventional air compressors. Block 13 has an internal coolant passage 42 leading to openings in the top of the block which index with openings in head 20. The block 13 contains the usual cylinder walls 43 and reciprocating piston 44 which form with the valve assembly 63 what is herein referred to as a compression chamber 49.

As shown in FIG. 3, the cylinder head apparatus 20 includes an inner air receiving chamber 45 formed by top, bottom, side and end wall portions arranged in an essentially oblong shape which join with four similar hollow cylindrical shaped centrally disposed wall portions 46 arranged lengthwise of the chamber and coaxial with the compression chambers 49. Incoming air as indicated by arrows in FIG. 3 flows through inlet passages 47 to deliver air to the compression chamber 49 during the intake stroke or downward travel of piston 44.

Compressed air outlet passages 48 are formed between a surface of the bottom wall portion of the receiving chamber and a lower portion of the adjoining central wall portion 46. Each air outlet passage 48 is coaxial and more specifically concentric with each air inlet passage 47 and functions to pass compressed air from the air compression chambers into the air receiving chamber 45.

As is particularly shown in FIG. 6, the interior of the air receiving chamber 45 includes narrower passage portions designated generally by numeral 51 between both sides of each central wall portion 46 and the adjoining side wall of the chamber, Wider passage portions designated generally by numeral 52 are formed between the opposing side walls of the chamber 45. These narrower passages 51 form at and more specifically adjacent and above each discharge passage outlet 48 a series of interconnected venturi-like passage portions having a common air outlet 19 at one end of the receiving chamber 45. The narrow portions 51 are further narrowed oppositely and on each side of each central wall portion 46 by an annular projecting surface portion 54 formed on the otherwise essentially flat inner surface of the side wall of the receiving chamber 45 which acts to further converge the air flow at each venturilike passage portion 51. Suitable wall sections 55 are formed in the chamber for the inner bolt holes within the chamber 45 between adjoining central wall portions 46.

The inner receiving chamber 45 has an essentially oblong cooling jacket 57 arranged in encompassing and spaced relation thereto forming a cooling passage 58 or aftercooler on all sides thereof to cool the compressed air delivered into the receiving chamber. Coolant such as water is delivered from the cylinder block passage 42 through suitable apertures 59 formed in the bottom wall of the jacket 57 and the coolant after circulating in the coolant passage 58 then passes through an outlet 61 shown in one end of the cooling jacket which passes the coolant to a radiator.

A recessed portion 62 is formed in the bottom wall of the head apparatus 20 which is arranged in fiow communication with the central air inlet passage 47 and discharge outlet passage 48 and more specifically is coaxial with the air inlet passage and associated compressor cylinder 43. This recessed portion 62 is shaped for receiving an annular pressure operated valve assembly 63 depicted somewhat schematically in FIG. 3 having an air intake port 64 into which the incoming air from the inlet passage 47 is drawn into the associated compressor chamber 49 on the intake stroke of the piston and air outlet ports 65 on each side of the inlet port 64 through which compressed air is forced from the associated compressor chamber 49 into the receiving chamber 45 through the outlet passage 48 on the discharge stroke of the piston. In the arrangement shown in FIG. 3, the top of the valve assembly 63 is shown to abut against the lower end of the inner cylindrical wall portion 46 and seat in an annular notched portion 66 in the bottom wall of the receiving chamber and is clamped in position between the head apparatus 20 and the cylinder block 13. The coolant passage 58 is arranged to open adjoining the valve assembly 63 for maximum valve cooling.

Valve assembly 63 forms no part of the present invention and may be of a variety of known pressure operated types presently in use or may consist of mechanical actuated intake and/or discharge valves. There is also provided a conventional unloader valve mechanism 67 shown as operatively associated with pressure operated valve assembly 63 which functions to reciprocate up and down to close and open the intake port 64 and maintains the port 64 open in response to a suitable signal line 25 when the storage tank in the system reaches a predetermined pressure amount.

In the arrangement shown in FIG. 6, the discharge ports 65 are generally arcuate in shape and are preferably positioned essentially below the narrower passage portions 51 on each side of the cylindrical central wall portion so that compressed air discharged into the receiving chamber from an associated compression chamber is directed upwardly through ports 65 and associated outlet passages 45 and into this narrower portion 51 and then through the other venturi-like sections 51 produce an area of reduced pressure for the other compression chambers 49. This reduced pressure at the other discharge passage outlets 51, which are in the general area of the discharge valves 65, assists in evacuating each associated compression chamber and thereby increases the output capacity c1- volumetric efficiency of the compressor. It is understood that the position of the discharge ports shown is a preferred arrangement but that a variety of sizes and shapes of discharge ports may be used.

In the continuous operation of the compressor, compressed air discharge of each compression chamber 49 is carried out in a preselected sequence of consecutive compressed air discharges from first one compression chamber 49 followed by another compression chamber 49 to successively produce or effect a low pressure area at the outlet of each compression chamber at the time of its discharge into the receiving chamber 45. This preselected sequence is accomplished by the timing or arrangement of the throws on the crankshaft 14.

While it is understood that these low pressure areas resulting from the venturi action may be produced to a certain degree with practically any sequence of consecutive discharges into the receiving chamber 45 because 01 an air flow throughout the receiving chamber, it has been found that a succession or progression of discharges in the direction of the outlet 19 of the receiving chamber provides the best results.

Specifically, as to a preferred succession, with reference to the front end of the head apparatus 20 and progressing to the air discharge outlet 19, a suitable firing or discharge order of the compression chambers is I, II, III and IV so designated in FIG. 1. Another suitable firing or discharge order with reference to the front end of the head apparatus 20 and progressing to outlet 19 is II, I, III and IV. Such a firing order has been found to produce a cumulative effect on the velocity of the air flow or successive additions in each succeeding venturilike section as it progresses toward the outlet 19. In the operating speed range of 1600 to 2400 r.p.m. the venturi effect which helps to evacuate each succeeding compression chamber is always present due to the mass flow in the direction of the receiving chamber outlet 19. By the selection of consecutive firing or discharge order in the direction of outlet 19 the venturi elfect increases through a buildup or cumulative effect of the air flow velocity with resulting decreases in pressure for each succeeding compression chamber 49.

Further, while a four cylinder compressor head has been shown and described, it is apparent that the venturi concept and the progressive buildup in each succeeding narrower passage portion is equally applicable to other numbers of cylinders and to multi-stage type compressors.

A test operation was run using a V8-265 Cummins diesel engine essentially arranged with cooling and secondary air storage tank 21 as depicted in FIG. 1 having four cylinders converted to air compressor components which had cylinder head apparatus similar to that depicted in FIGS. 2-6. The apparatus was found to develop on the order of 380 c.f.m. at a 100 p.s.i.g. final discharge pressure when operated at 2200 r.p.m. An approximate volumetric efiiciency and final discharge pressure curve 71 produced from these tests is shown on FIG. 7 along with a typical curve 72 of known single stage reciprocating air compressors. A comparison of these curves shows the apparatus embodying features of the present invention had a volumetric efficiency above 75% at 100 p.s.i.g. on curve 71 as compared with a volumetric efliciency of about 55% resulting taken from curve 72. A plot of the brake horsepower requirement against final discharge pressure, as shown on FIG. 7, produced from these test results shows an approximate curve 73 which may be compared with a typical curve 74 of known single stage reciprocating compressors. A comparison of these curves at 100 p.s.i.g. shows curve 73 to have a corresponding brake horsepower requirement of about 17 as compared to about 22 brake horsepower on curve 74.

Further tests of this apparatus indicated that when the compressor is unloaded (diaphram of the unloader valve 67 holds holds the intake port open) the apparatus is capable of delivering about 95% of the rated power from the four cylinders of the diesel power side to the flywheel 24 which would be on the order of 1101 15 HP at 2200 r.p.m. When the compressor side is fully loaded (i.e., pumping at p.s.i.g.) there is about 40 HP surplus power available from the flywheel. Thus the portable apparatus as depicted in FIG. 1 may be self propelled or power auxiliary equipment such as a Welder, sprayer, drill or the like.

While the present invention has been described with reference to particular structure there is no intent to limit the spirit and scope of this invention to such structure except as defined by the appended claims.

I claim:

1. Compressor apparatus for a piston-type compressor having a plurality of spaced air compression chambers comprising a body forming an elongated air receiving chamber having an air discharge means in one wall thereof, said receiving chamber having a series of successive venturi-like sections, each said section being in flow receiving relation to an outlet of one of the compression chambers so that a compressed air discharge through one of the air outlets into the receiving chamber produces an air flow in said receiving chamber to provide a low pressure area in the venturi-like passage portion of other of said compressed air outlets to assist in evacuating the compression chambers.

2. Compressor apparatus for a piston-type compressor having a plurality of spaced air compression chambers including valve controlled means having a plurality of air inlets and air outlets for passing air into each compression chamber and from each compression chamber in separate streams, said apparatus comprising an air receiving chamber arranged in a flow-coupled relation to each of said compression chamber outlets having at least one common air discharge means for passing air from the receiving chamber, said receiving chamber having at least one narrower passage portion arranged in receiving relation to each said compressed air outlet so that a compressed air discharge through one of said compressed air outlets into the receiving chamber produces an air flow in said receiving chamber to provide a low pressure area in the narrower passage portion of other of said compressed air outlets to assist in evacuating the compression chambers.

3. Compressor apparatus as set forth in claim 2 wherein the compressed air discharge through an upstream of said narrower passage portions provides a low pressure area in a plurality of successively arranged downstream narrower passage portions.

4. Compressor apparatus as set forth in claim 2 wherein the compressed air discharge into each succeeding downstream narrower passage portion is in a consecutive order in the direction of the discharge means of the receiving chamber to provide a cumulative effect on the velocity of the air mass flow in each succeeding downstream narrower passage portion.

5. Compressor apparatus as set forth in claim 2 wherein said receiving chamber includes a cooling jacket arranged in an encompassing relation thereto for circulating a coolant to cool the air delivered into the receiving chamber through each of said outlets.

6. Compressor cylinder head apparatus arranged to mount in covering relation to a plurality of spaced air compression chambers in a piston-type compressor including a valve controlled means having plurality of air inlet and air outlet ports for alternately passing air into and out of each compression chamber in separate streams, said head apparatus comprising a body forming an air receiving chamber having a plurality of centrally disposed air inlet passages for passing air to each of the air inlet ports and an air outlet passage disposed outwardly and coaxial with each air inlet passage for passing air from each air outlet port into the chamber, said receiving chamber having a narrower passage portion at each said compressed air passage outlet to form a series of flow coupled essentially venturi-like sections interiorly of the chamber and terminating in at least one discharge outlet for the air receiving chamber whereby a compressed air discharge through one of said compressed air outlet passages into the receiving chamber produces an air flow in said receiving chamber to provide a low pressure area in the venturi-like section of other of said compressed air outlets.

7. Compressor cylinder head apparatus as set forth in claim '6 wherein a bottom wall portion of the body is arranged to seat on a compressor chamber block and includes a recessed portion in flow communication with an air inlet passage and an air outlet passage in which a valve means is disposed to be clamped between the head and block portion.

8. Compressor cylinder head apparatus as set forth in claim 6 wherein said air receiving chamber is essentially oblong in shape and has an essentially oblong cooling jacket disposed in enclosing relation thereto providing a cooling passage to cool essentially all sides thereof.

9. Compressor cylinder head apparatus as set forth in claim 8 wherein a bottom Wall portion of said cooling jacket has a plurality of apertures arranged to aline with apertures in a cooling jacket for a compression chamber block for circulation of coolant therethrough.

10. Compressor cylinder head apparatus as set forth in claim 6 wherein said air inlet passages are formed by a plurality of hollow cylindrical wall portions disposed in substantially spaced and essentially parallel relation so as to be coaxial with the compression chambers.

11. A compressor cylinder head apparatus as set forth in claim 10 wherein said narrower portions are formed between adjacent surfaces of the hollow cylindrical wall portions being joined to an inner side, top and bottom wall portions of the receiving chamber.

12. A compressor cylinder head apparatus as set forth in claim 11 wherein said inner side wall portion has an inner annular projecting surface portion oppositely of each cylindrical wall portion to narrow the passage portion and further converge the air flow in each venturilike section.

13. A portable compressor system comprising a mobile frame arranged for supporting a compressor assembly including a multiple chamber reciprocating type compressor having a plurality of air inlets and at least one compressed air outlet for each inlet, drive means coupled in a driving relation to the compressor, an air storage tank, an air receiving chamber arranged in a flow coupled relation to each of the outlets, means for passing air from the receiving chamber to the air storage tank, said receiving chamber including one of a series of venturilike flow related passage portions internally thereof disposed at each outlet, means for timing the discharge of each compressor chamber so that a compressed air discharge through one of said air outlets produces an air flow in said receiving chamber to provide a low pressure area in a venturi-like passage portion at other of said compressed air outlets at the time of compressed air discharge through said other of said air outlets.

14. A portable compressor system as set forth in claim 13 wherein said drive means is an internal combustion engine having an auxiliary power takeoif from a flywheel mounted on the crankshaft of the engine.

15. A portable compressor system as set forth in claim 13 wherein said compressor and engine are formed as an integral unit using a single V-type cylinder block with pistons in the cylinders on one side forming the power to drive the pistons in the compressor cylinders on the other side.

References Cited UNITED STATES PATENTS 2,084,670 6/1937 Crittenden.

2,151,825 3/1939 Aikman 230l81 X 2,310,520 2/1943 Esnault-Pelterie 230-238 X 3,136,477 6/1964 Nicholas 230l8l X 3,153,508 10/1964 Sawyer 23030 X 3,193,193 7/1965 Gerteis 230238 X 3,244,106 4/1966 Guy 1035 3,349,994 10/1967 Bloom 230-45 DONLEY J. STOCKING, Primary Examiner W. J. KRAUSS, Assistant Examiner U.S. Cl. X.R. 

